Electronic flash unit and manufacturing method thereof

ABSTRACT

The electronic flash unit disclosed comprises: a transformer ( 14 ) to vary voltages of a power supply; an accumulator ( 16 ) composed of a main capacitor ( 17 ) to charge an electric energy supplied from the transformer ( 14 ); a lamp unit ( 4 ) provided with a flashlamp ( 20 ), set inside of a reflector ( 19 ), that flashes by discharging of energy storages in the main capacitor ( 17 ) upon applying a voltage on a trigger terminal ( 21 ); and a trigger circuit ( 10 ) to generate the voltage to apply on the trigger terminal ( 21 ), wherein at least the lamp unit ( 4 ) is coated with an insulation material.

RELATED APPLICATIONS

This application is a 371 of International Application No.PCT/JP02/12430, filed Nov. 28, 2002, which in turn claims the benefit ofJapanese Patent Application No. 2001-365882 filed on Nov. 30, 2001, thecontents of which Applications are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to an electronic flash unit employing aflashlamp, a valuable artificial light source, to take photographs usingcamera (an imaging apparatus) equipped with a silver film or anelectronic imaging element such as charge-coupled device (CCD) orcomplementary metal-oxide semiconductor (CMOS) sensor as a photographicsensitive material, and a manufacturing method thereof.

BACKGROUND ART

FIG. 7 shows a typical electronic flash unit basically comprising:flashlamp 20 for instance a xenon lamp (set inside of a reflector, butnot shown); lamp unit 4 provided with trigger terminal 21; triggercircuit 10 provided with trigger coil 11 and trigger capacitor 13;transformer 14 composed of transformer coil 15; accumulator 16 composedof main capacitor 17; and power source 22 composed of DC source 23. Maincapacitor 17, on a charged condition of for instance 300 V by DC source23, allows trigger circuit 10 to apply a several kV of trigger voltageon trigger terminal 21 of flashlamp 20, thereby causing flashlamp 20 toignite for flashing by discharging the power storage in main capacitor17.

Other types of electronic flash units would have dimming circuits 25provided with Insulated Gate Bipolar Transistor (IGBT) 26, opticalsensor 27 or the like added to the aforesaid configuration to controlthe amount of flashing light by dimming circuits 25.

A lot of conventional electronic flash units like described above areused in various kinds of cameras such as silver film cameras, well knowndigital cameras employing CCD or CMOS sensor as an imaging element, andsingle-use-cameras having a simplified structure of a film incorporatedwith a lens unit and the electronic flash unit built-in the camera body.

As portable telecommunication terminals or cell-phones capable oftransmitting stored images using built-in digital camera have becomepopular in the market, electronic flash units detachable to thecell-phones have also begun to be provided. Along with recent trends ofdownsizing in cameras and cell-phones, or built-in design incell-phones, a more compact sized electronic flash units are required tomeet the market needs.

Downsizing of the electronic flash unit, however, cannot be achievedwithout solving the problem of so-called “trigger leak”. The triggerleak means a poor flashing due to occurring a creeping discharge thatresults in an ineffective ionization in flashlamp 20 caused by adecrease in clearance between trigger terminal 21 provided on the glassbulb of flashlamp 20 and main electrode 20 a of flashlamp 20.

SUMMARY OF THE INVENTION

The electronic flash unit comprises: a transformer to vary voltages of apower supply; an accumulator composed of a main capacitor to charge anelectric energy supplied from the transformer; a lamp unit provided witha flashlamp, set in a reflector, that flashes by discharging theelectric energy storage in the main capacitor upon applying a voltage ona trigger terminal; and a trigger circuit to generate the voltage toapply on the trigger terminal, wherein at least the lamp unit is coatedwith an insulation material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exploded perspective view from the front side of theelectronic flash unit used in preferred embodiment 1 of the presentinvention.

FIG. 2 shows an exploded perspective view from the front side of thelamp unit used in preferred embodiment 1 of the present invention.

FIG. 3 shows a perspective view from the backside of the lamp unit usedin preferred embodiment 1 of the present invention.

FIG. 4 shows a partial perspective view of a different embodiment of thelamp unit used in preferred embodiment 1 of the present invention.

FIG. 5 shows a cross-sectional side view of the electronic flash unitused in preferred embodiment 1 of the present invention.

FIG. 6A shows a perspective view from the backside of the electronicflash unit used in preferred embodiment 2 of the present invention.

FIG. 6B shows a perspective view from the front side of the electronicflash unit used in preferred embodiment 3 of the present invention.

FIG. 6C shows a perspective view from the front side of the electronicflash unit used in preferred embodiment 4 of the present invention.

FIG. 6D shows a perspective view from the front side of the electronicflash unit used in preferred embodiment 5 of the present invention.

FIG. 7 shows an electric block diagram of a typical electronic flashunit.

FIG. 8 shows a cross-sectional view of an exemplary embodiment of theelectronic flash unit in which a reflector is filled internally withinsulating material.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Now, the preferred embodiments of the present invention are describedwith reference to the drawings.

Preferred Embodiment 1

FIG. 1 shows an example of electronic flash units in which lamp unit 4,trigger circuit 10, transformer 14, dimming circuit 25 and accumulator16 are shown coated with an insulation material individually.

The electronic flash unit explained in preferred embodiment 1, capableof connecting to an earphone jack of a cell-phone having built-indigital camera using CCD or CMOS sensor detachable freely, flashes uponreceiving power supply and signals to start photographing from thecell-phone. As shown in FIG. 1, the electronic flash unit includeselements of: circuit board 3; lamp unit 4 except optical surface 5 a,exposed critically through opening 2 a formed in the front half ofhousing 2, of optical panel 5; and base 6 a of plug (external terminal)6 in a hermetically sealed generally box shaped resin molded housing 2capable of separating into halves.

Circuit board 3 has patterned circuits to drive the electronic flashunit. The pattern in circuit board 3 comprises circuit elementsconnected electrically: various kinds of lead wires such as lead wire 7to the plug, lead wire 8 to flashlamp 20, and lead wire 9 to triggerterminal 21; trigger circuit 10 including trigger coil 11, triggercapacitor 13 (not shown) or the like; dimming circuit 25 including IGBT(not shown), optical sensor (not shown) or the like; transformer 14composed of transformer coil 16; and accumulator 16 composed of maincapacitor 17.

Lamp unit 4, other than aforesaid optical panel 5, comprises: resinmolded frame 18 fixed to circuit board 3; reflector 19; flashlamp 20provided with a conductive layer, for instance a transparent conductivelayer, formed on the outer surface of glass bulb; and trigger terminal21 connected electrically to the conductive layer formed on the glassbulb of flashlamp 20 through reflector 19 as shown in FIGS. 2 and 3.

Reflector 19 is fitted to opening 18 a of frame 18 from the front.Flashlamp 20 is inserted inside of reflector 19 from side openings 19 aof reflector 19 projecting to the back of opening 18 a of frame 18. Apair of lead wires 8 to flashlamp 20 is soldered to each of mainelectrodes 20 a of flashlamp 20 respectively. A lead wire 9 to triggerterminal 21 is soldered to trigger terminal 21 appressed to the back ofreflector 19. Optical panel 5 is fitted to the front surface of frame18, or optical panel 5, in a condition of being fitted to opening 2 a ofhousing 2, is included in housing 2 eventually.

Reflector 19 is made of a bright aluminum sheet cut into a predeterminedshape, formed into generally U-shaped and bent inward in edges,comprising a U-shaped cross-sectional or concavely curved inner surfaceto reflect a flash light and a pair of side panels, 19 b and 19 b, inboth right and left ends.

A pair of side panels 19 b are designed to provide side opening 19 awith a slightly larger dimension than the outer diameter of flashlamp20, causing both ends (including main electrodes 20 a) of flashlampinserted from a side opening 19 a to project out of side openings 19 aexternally.

Flashlamp 20 has a structure of a straight glass tube with metal rodmain electrodes 20 a sealed in both ends, partially extending externallyalong axial direction, and with a filling gas in the tube of forinstance xenon.

One of main electrodes 20 a of flashlamp 20 is connected to lead wire 8connected to main capacitor 17 and another main electrode 20 a isconnected for instance to lead wire 8 grounded directly.

Trigger terminal 21 is made of a copper sheet bent arc shapedcorresponding to reflector 19. Practically, the copper sheet, reflector19 and the conductive layer provided on the glass bulb of flashlamp 20all together make up trigger terminal 21. The copper sheet, however, isnot necessary if lead wire 9 to trigger terminal 21 can be soldereddirectly to reflector 19 or to the surface of glass bulb of flashlamp20.

Extending reflector 19 partially to act as a terminal, portion 19 c canbe coupled directly with high voltage terminal 11 a of trigger coil 11as shown in FIG. 4. The configuration can not only make lead wire 9 totrigger terminal and the copper sheet unnecessary but also can saveworks of pasting the copper sheet or soldering lead wire 9 to triggerterminal 21.

As aforementioned and shown in FIG. 1, housing 2 contains; circuit board3 including various circuit elements, lamp unit 4 and base 6 a of plug(external terminal) 6 in a hermetically sealed condition.

Though the relevant positions are sealed hermetically in fitting opticalsurface 5 a of optical panel 5 to opening 2 a of housing 2 and infitting plug base 6 a of plug 6 to opening 2 b provided at separatesurfaces of the housing halves, housing 2 is not sealed in a completeair-tight condition.

The reason is that housing 2 is provided with a pair of fine throughholes 2 c and 2 d. Through holes 2 c and 2 d are formed halved at theseparate surfaces of housing 2 to form circular holes by combininghalves of housing 2. The positions to provide through holes 2 c and 2 dare not restricted particularly. Among these two, through hole 2 c is towork for filling housing 2 with an insulation resin (insulationmaterial), and the other through hole 2 d is to let air in housing 2 outat the resin filling. Specifically, housing 2 is filled with theinsulation resin using a filling nozzle fitted in through hole 2 cformed at the bottom surface of housing 2, allowing air in housing 2 toleave via through hole 2 d formed at the top surface of housing 2.

Number of hole is not restricted within one pair if the resin fillingand air releasing will be performed well, and hole other than circularshaped may be acceptable. Polyurethane, silicone, epoxy, polyimide orthe like can be adopted for the insulation resin, and glasses may beused as insulation materials.

A feasible configuration has a reflector filled with an insulationmaterial internally if a glass or resin, transparent or translucent,with insulation property is adopted as the insulation material. In thiscase, the internal of reflector as well as lamp unit is filled with theglass or resin for insulation at the same time. The glass or resin,transparent or translucent, can effectively prevent a loss in incidentlight intensity of flashlamp through the air atmosphere inside of thereflector to optical panel that occurs when the glass or resin is notapplied, enabling to increase in performance characteristics of theelectronic flash unit.

Additionally, the resins can be mixed with glass beads to improve lightdiffusion effects.

As described above, the electronic flash unit elements consisting ofcircuit board 3 (including trigger circuit 10, transformer 10,accumulator 16, dimming circuit 25 or the like) and lamp unit 4 are allallowed completely coated with the resin, since the sealed inside spaceof housing 2 is filled with a resin entirely as shown in FIG. 5 (housing2 under a condition filled with a resin is not shown). Above all,positions required highly insulated such as the clearance between mainelectrodes 20 a and 20 a of flashlamp 20 and trigger terminal 21(reflector 19), terminals 11 a of trigger coil 11, transformer coil 15(especially, secondary coil) and terminals of main capacitor 17(especially, high voltage terminal) are electrically insulatedcompletely, enabling to prevent the trigger leak or possible electricshocks at breakage of housing 2 from occurring. Additionally, theconfiguration can improve their own insulation characteristics oftrigger coil 11 and transformer coil 15 and can strengthen resistancesto dropping impacts or the like.

Preferred Embodiment 2

FIG. 6A shows an example of lamp unit 4 in FIG. 7 coated with aninsulation material.

The electronic flash unit used in preferred embodiment 2 includes lampunit 4 alone in housing 2 independently as shown in FIG. 6A. Theconfiguration is suitable for a detachable lamp unit to an electronicflash unit (or a camera body or cell-phone body, in case of a camera orcell-phone with a built-in electronic flash unit).

Box-shaped housing 2, provided with optical panel 5 in one surface andopen in the opposite surface, includes reflector 19, flashlamp 20 andtrigger terminal 21.

Housing 2 includes a pair of lead wires 8 and 8 to flashlamp 20, andlead wire 9 to trigger terminal including soldered ends.

Housing 2 is filled with an insulation resin under this condition(seeFIG. 8).

Consequently, the clearances between main electrodes 20 a and 20 a offlashlamp 20 and trigger terminal 21 (reflector 19) are electricallyinsulated completely, enabling to prevent the trigger leak or possibleelectric shocks at breakage of housing 2 from occurring and tostrengthen resistances to dropping impacts or the like.

Preferred Embodiment 3

FIG. 6B shows an example of lamp unit 4, trigger circuit 10, transformer14 and dimming circuit 25 in FIG. 7 coated with an insulation material.The electronic flash unit used in preferred embodiment 3 includes lampunit 4 and circuit board 3 in an independent housing 2, exposing maincapacitor 17 out of housing 2 as shown in FIG. 6A.

Box-shaped housing 2 provided with optical panel 5 in one surface,includes reflector 19, flashlamp 20, trigger terminal 21 and circuitboard 3 carrying circuit elements (trigger circuit 10, transformer 14,dimming circuit 25 or the like) except main capacitor 17.

Lead wires connected to terminals of main capacitor 17 and lead wires toreceive electric power or signals externally are connected to internalcircuit board 3 through housing 2.

Housing 2 is filled with an insulation material under this condition.Consequently, the clearances between main electrodes 20 a and 20 a offlashlamp 20 and trigger terminal 21 (reflector 19), terminals 11 a oftrigger coil 11 and transformer coil 15 are electrically insulatedcompletely, enabling to prevent the trigger leak or possible electricshocks at breakage of housing 2 from occurring and to strengthenresistances to dropping impacts or the like.

Preferred Embodiment 4

FIG. 6C shows an example of lamp unit 4, trigger circuit 10, transformer14, dimming circuit 25 and a terminal of main capacitor 17 in FIG. 7coated with an insulation material.

The electronic flash unit used in preferred embodiment 4 includes lampunit 4, circuit board 3 and a portion of main capacitor 17 in anindependent housing 2, exposing the other portion of main capacitor 17(except terminal) out of housing 2 as shown in FIG. 6C.

Box-shaped housing 2 provided with optical panel 5 in one surface,includes reflector 19, flashlamp 20, trigger terminal 21 and circuitboard 3 carrying circuit elements (trigger circuit 10, transformer 14,dimming circuit 25, accumulator 16 or the like).

Housing 2 includes terminal side half of main capacitor 17 while theother half of explosion-protection valve side is exposed out of housing2 critically. Lead wires to receive electric power or signals externallyare connected to internal circuit board 3 through housing 2.

Housing 2 is filled with an insulation material under this condition.Consequently, the clearances between main electrodes 20 a and 20 a offlashlamp 20 and trigger terminal 21 (reflector 19), terminals 11 a oftrigger coil 11, transformer coil 15 and terminal of main capacitor 17are electrically insulated completely, enabling to prevent the triggerleak or possible electric shocks at breakage of housing 2 from occurringand to strengthen resistances to dropping impacts or the like.

Explosion-protection valve 17 a provided in main capacitor 17 is toprotect whole of the capacitor from breakage by blowing out itself at anabnormal increase in inner pressure of main capacitor 17. The valve isintroduced on the assumption of possible failures. Though, typically, itseems unlikely for explosion-protection valve 17 a to blow out, it wouldbe a wise measure to expose a relevant portion out of housing 2beforehand to protect housing 2 from damaging influences if possiblefailures are assumed.

Therefore, housing 2 is not influenced even in an abnormal condition(over current) of main capacitor 17, as explosion-protection valve 17 ais positioned exposed outside of housing 2.

Preferred Embodiment 5

FIG. 6D is an example showing lamp unit 4, trigger circuit 10,transformer 14, dimming circuit 25 and a terminal of main capacitor 17in FIG. 7 are coated with an insulation material.

The electronic flash unit used in preferred embodiment 5 includes lampunit 4, circuit board 3 and a portion of main capacitor 17 in anindependent housing 2, exposing the other portion of main capacitor 17(except terminal) and projection terminal 24 to receive electric powerand signals externally from housing 2 as shown in FIG. 6D.

A feasible configuration further comprises a projection terminal toconnect to the power supply electrically that protrudes out of thehousing. Namely, the electronic flash unit can be a detachable device ifcamera or cell-phone has a terminal capable of connecting to theprojection terminal

Box-shaped housing 2 provided with optical panel 5 in one surface,includes reflector 19, flashlamp 20, trigger terminal 21 and circuitboard 3 carrying circuit elements (trigger circuit 10, transformer 14,dimming circuit 25, accumulator 16 or the like). Housing 2 includes mostof terminal side of main capacitor 17 while the remaining side withexplosion-protection valve 17 a is exposed out of housing 2. Projectionterminal 24 exposing out of housing 2 critically is connected to circuitboard 3 through inside of housing 2 or an end of circuit board exposedout of housing 2 critically acts as a projection terminal.

Housing 2 is filled with an insulation material under this condition.Consequently, the clearances between main electrodes 20 a and 20 a offlashlamp 20 and trigger terminal 21 (reflector 19), terminals 11 a oftrigger coil 11, transformer coil 15 and terminal of main capacitor 17are electrically insulated completely, enabling to prevent the triggerleak or possible electric shocks at breakage of housing 2 from occurringand to strengthen resistances to dropping impacts or the like.

Other Preferred Embodiments

The present invention is not so limited to the aforesaid preferredembodiments but is susceptible to various changes without departing fromthe scope of the invention.

For instance, if the housing is used as a package of the electronicflash unit (including a case when the housing is used for an element ofthe electronic flash unit for instance lamp unit 4 alone), the housingcan be applied a conductivity to perform protective shield effectsagainst electric or magnetic noises. The housing should, preferably, befilled with an insulation resin after inner (or outer) surface of thehousing is provided with a shield layer by conductive resin coating ormetal plating.

The configuration of housing with the shield layer can shut off electricnoises properly.

Additionally, the description, “internal elements are hermeticallysealed in the housing”, does not mean to shut off in-and-out air flowingcompletely but means not to leak out the filled resin. Therefore, in allof the aforementioned descriptions, housing 2 does not require a highaccuracy as to secure a perfect airtight condition. However, to reduceinward and outward air flowing paths, optical panel 5 should preferablybe made integrally with housing 2 using a same material. Consequently,optical panel 5 is not required to form an attachable periphery tohousing 2 or housing 2 does not need to have an opening provided with aframe mountable to optical panel 5, resulting in a contribution to thedownsizing of electronic flash unit due to thin thickness optical panel5 and compact sized housing 2.

Additionally, if the configuration of optical panel 5 molded integrallywith housing 2 is adopted instead of disposed in front of the opening ofreflector 19 as a separate parts, low profile optical panel 5 and downsized housing 2 can be achieved, resulting in a downsizing of theelectronic flash unit. Moreover, the configuration can provide a highquality electronic flash unit, with no danger of leaking the filledinsulation materials out of the electronic flash unit as no jointsurfaces exist between optical panel 5 and housing 2.

Additionally, the applying way of insulation resins are not so limitedto the insulation resins poured into the housing through holes or thelike externally. A feasible method for instance would be to providerespective halves of a housing with the insulation resin beforehand andto complete a housing by combining the respective halves.

Additionally, the filling insulation resin should preferably have acertain degree of elasticity. This is to prevent the housing or partsincluded in the housing from being damaged due to an expansion ofinsulation materials caused by heats generated in elements of theelectronic flash unit.

Moreover, to prevent air bubbles from generating in the insulationmaterials, the housing is allowed pumped to a vacuum pressure during orafter the resin filling and then the insulation resins should preferablybe hardened under a pressure higher than the vacuum pressure.

Additionally, the aforesaid resin filling process pumps air in thereflector also, causing to fill inside of the reflector with the resin.However, the resin can be prevented from pouring inside of thereflector, if gaps between side openings of the reflector and theflashlamp, and between both side plates are sealed by some sealing means(for instance, a silicone bond or a rubber bushing). (No insulationresin pours into from the front opening, as the optical panel closes theopening).

Additionally, the reflector filled with the insulation resin has anadvantage to prevent a loss in incident light through the air atmosphereinside of the reflector to optical panel resulting in no decrease inlight intensity (in case of a transparent insulation resin), but has adisadvantage to reduce light diffusion effects of a light diffusionsurface formed on the back surface of the optical panel due to theapproximate refraction factors of the optical panel and the insulationresin.

The configuration of the reflector filled with the insulation resin,therefore, should preferably adopt an insulation resin mixed with adiffusion agent as an additive, and glass beads for instance used as adiffusion agent will improve the light diffusion effects.

Moreover, instead of the housing used as a mold to fill with theinsulation resin as described in the aforesaid preferred embodiments, apossibility would be the electronic flash unit regardless of the housing(covered by a housing if needed), wherein elements of the electronicflash unit (all of or a part of) are set in another mold and releasedfrom the mold after the mold is filled with the insulation resin.

Additionally, to produce the electronic flash unit contained in thehousing filled with the insulation resin, internal elements of theelectronic flash unit are disposed after selected into two groups: highvoltage group to be insulated (for instance, the lamp unit, the triggercircuit, at least secondary terminal of the transformer, at least highvoltage terminal of the main capacitor or the like); and the remaininglow voltage group.

If filled-in insulation resins are hardened disposing elements in highvoltage group on lower positions and elements in low voltage group onupper positions in the housing, the elements in high voltage group canbe insulated properly as the elements in high voltage group is securelycovered in the insulation resin even in up and down flowing movements inupper portions of the insulation resin caused by bubbling under a vacuumcondition in case of the housing filled with the insulation resinincompletely.

Moreover, members such as lamp unit 4 or the like to be filled withinsulation materials should preferably be filled with the insulationmaterials once coating the surface with the insulation resin by dippingor the like. This is to achieve an effective insulation coating as gapsin each parts are filled with the insulation resin reliably.

As described above, among elements of the electronic flash unitdisclosed in the present invention at least lamp unit is coated with theinsulation resin to insulate the clearance between the trigger terminal(or reflector itself, or the reflector attached to the triggerterminal), enabling to prevent the trigger leak from occurring properly.Consequently, a further downsizing of the electronic flash unit can beachieved by solving the trigger leak problem.

INDUSTRIAL APPLICABILITY

The present invention relates to an electronic flash unit using aflashlamp as a light source and a manufacturing method thereof. Theelectronic flash unit can prevent the occurrence of the trigger leaksaccompanied by downsizing significantly, while achieving a compactdesign.

1. An electronic flash unit comprising: a transformer to vary voltagesof a power supply; an accumulator composed of a main capacitor to chargean electric energy supplied from the transformer; a lamp unit providedwith a flashlamp, set inside of a reflector, that flashes by dischargingof energy storages in the main capacitor upon applying a voltage on atrigger terminal; and a trigger circuit to generate voltages to apply onthe trigger terminal, wherein at least the lamp unit is completelyinsulated by an insulation material by filling the insulation materialin to a mold after positioning the lamp unit in the mold, wherein themold includes an input hole through which the insulation material issupplied into the mold so as not to have a space which causes a creepingdischarge, and a vent hole for exhausting air within the mold while theinsulation material is supplied into the mold wherein the lamp unitrequires at least 300 v for operation.
 2. The electronic flash unit ofclaim 1, wherein the insulation material is a glass or an insulationresin, transparent or translucent, with insulation properties and thereflector is filled internally with the glass or the insulation resin.3. The electronic flash unit of claim 2, wherein the insulation resin ismixed with glass beads.
 4. The electronic flash unit of one of claims 1to 3, wherein the trigger circuit is insulated with the insulationmaterial.
 5. The electronic flash unit of claim 4, wherein thetransformer is insulated with the insulation material.
 6. The electronicflash unit of claim 5, wherein at least terminals of the main capacitorare insulated with the insulation material.
 7. The electric flash unitof one of claims 1 to 3, wherein the mold includes a housing used as apackage, and the housing is filled with the insulation material.
 8. Theelectric flash unit of claim 7, wherein an explosion-protection valve ofthe main capacitor is exposed critically out of the housing.
 9. Theelectric flash unit of claim 7, further comprising a projection terminalto connect to the power source electrically, wherein an end of theprojection terminal is exposed critically out of the housing.
 10. Theelectric flash unit of claim 7, wherein an optical panel disposed facinga front opening of the reflector is molded integrally to the housing.11. The electric flash unit of claim 7, wherein a protective shieldlayer is formed on the housing.
 12. The electric flash unit of claim 7,wherein a high voltage terminal of trigger coil is connected to thereflector directly.
 13. The electric flash unit of claim 12, wherein aportion of the reflector is extended to connect to said high voltageterminal of the trigger coil.